Robert Franks

We are using the diversity of Mimulus (Monkey Flower) species to identify the molecular mechanisms of reproductive isolation and speciation. Our work will significantly contribute of our understanding of the molecular, ecological and evolutionary bases of speciation and biodiversity generation.

Enabling the next generation of sustainable farms requires a paradigm shift in resource management of the two most critical agricultural inputs for food production: water and nitrogen (N) - based fertilizer. Inefficient management of these resources increases food production costs, decreases productivity, and impacts the environment. An integrated approach is needed to improve the sustainability and efficiency throughout the production chain. Emerging (bio)electrochemical (BEC) technologies offer alternatives to conventional, fossil-fuel intensive N fertilizer production. Recently our team has demonstrated two game-changing BEC technologies: 1) microbial conversion of nitrogen gas into ammonium, and 2) plasma generation of N species (e.g., nitrate, nitrite) and other reactive species in water for fertilization and anti-pathogen benefits. We will integrate these technologies to produce BEC, N-based fertilizer, and with advanced sensor and delivery systems, we will precisely supply fertilizers for sustainable precision agriculture. Our proposed approach focuses on the development of a novel ????????????????BEC fertigation on demand system??????????????? by using sensor-driven data and molecular analyses to investigate BEC fertigation impact on the plants?????????????????? growth, adaptation, and microbiome; its impact on food safety and quality, and its economic feasibility for on-farm deployment.

Here we propose to determine the evolutionary genetic basis underlying species divergence in endosperm development and embryogenesis and their consequences for hybrid seed lethality, a principal isolating barrier in the Mimulus guttatus sp. complex [1]. We focus on two diploid species, the serpentine endemic M. nudatus and the widespread M. guttatus, which do not hybridize in the wild despite their coexistence and shared pollinators. Controlled interspecific crosses yield two hybrid seed types: hybrid seed that exhibit early arrested endosperm development and hybrid seed with relatively normal early endosperm development but late endosperm deficiency. We integrate molecular and developmental experiments, RNA sequencing, and high-throughput genome mapping to elucidate the genetic mechanisms contributing to seed abortion in M. guttatus x M. nudatus crosses.

The coordination of spatial patterning cues and cellular proliferation underlies diverse processes from cancerous growth to reproductive development. A long-term objective of my research program is to understand how proliferative cues are coordinated with spatial information during organogenesis. In Arabidopsis thaliana this coordination of patterning and proliferation is necessary within the carpel margin meristem (CMM) to generate ovules that when fertilized will become seeds. The CMM is a vital meristematic structure with a unique pattern of organ initiation, and novel mechanisms of meristematic development that are not yet well characterized. In the previous funding period we demonstrated that the SEUSS (SEU) and AINTEGUMENTA (ANT) transcription factors regulate patterning events within the gynoecium that are critical for carpel margin meristem and ovule development. Our genetic analysis demonstrates that SEU and ANT share a partially redundant and overlapping function essential for proper CMM development. As SEU and ANT do not share sequence similarity, the molecular basis for this redundancy is not understood. We propose that the SEU and ANT activities synergistically converge at key transcriptional nodes. A node in this sense is a gene or a set of related genes that requires the combined activities of SEU and ANT for its proper expression. Our recently published transcriptomic analysis identified many putative nodes encoding known transcriptional regulators. By studying these candidate nodes we hope to better understand the transcriptional hierarchies that control CMM development and uncover the mechanistic basis of the synergistic action of SEU and ANT. Our transcriptomics study cannot determine if these nodes are directly or indirectly regulated by SEU or ANT activity. However, even if these node genes are indirectly controlled by SEU and ANT activity, their expression within the developing CMM suggests they may still play a critical functional role during CMM development. Furthermore, having now identified a set of genes that are enriched for CMM expression we are in a position to study the cis-regulatory elements that support gene expression within the CMM and the medial gynoecial domain. Here we propose to: 1) Identify direct targets of SEU regulation within the CMM to further refine the transcriptional hierarchy required for CMM development; 2) Develop a protoplast sorting protocol for gynoecial cells to enable a systems-biological analysis of developmental events within the CMM; 3) Determine the functional role of one of our high priority candidate genes during CMM development; and 4) Identify evolutionarily conserved cis-regulatory elements that support the expression of our candidate genes in the CMM. Intellectual Merit: Understanding the coordination of cellular proliferation and spatial patterning during organogenesis is of broad interest to scientists working in a diversity of fields. Completion of these specific aims will move us toward this future goal by illuminating the mechanistic basis for the overlapping functions of SEU and ANT during carpel margin meristem and ovule development. Additionally, we expect that by elucidating the molecular mechanisms of the synergistic action of SEU and ANT upon key transcriptional nodes, we will engender a greater understanding of the molecular underpinnings of non-additivity within transcriptional networks and the complexity of developmental programs. Past NSF funding for this project (IOS-0821896) has resulted in the publication of five articles in well-respected journals (two in Plant Physiology, and one each in Developmental Biology, PLoS One, and BMC Plant Biology). Broader impacts: I ensure a broad societal impact from my program by integrating my research efforts with my teaching and training responsibilities and by widely disseminating materials and results. Furthermore, I organize an outreach group that presents hands-on science demonstrations at local North Carolina middle schools. Additionally, our work on the mechanisms of CMM development may lea

The coordination of spatial patterning cues and cellular proliferation underlies diverse processes from cancerous growth to reproductive development. In Arabidopsis thaliana this coordination of patterning and proliferation is necessary within the carpel margin meristem to generate ovules that when fertilized will become seeds. In the previous funding period we demonstrated that the SEUSS (SEU) and AINTEGUMENTA (ANT) transcription factors regulate critical patterning events that support carpel margin meristem and ovule development. Our genetic analysis demonstrates that SEU and ANT share a partially redundant and overlapping function essential for proper seed formation. As SEU and ANT do not share sequence similarity, the molecular basis for this redundancy is not understood.